數據結構與算法 - C#實現N叉樹(1)

N叉樹的每一節點度數都相同，為N

using System;
using System.Collections;
namespace DataStructure
{
     /// <summary>
     /// NaryTree 的摘要說明。-----N叉樹
     /// </summary>
     public class NaryTree:Tree
     {
         // member variables
         PRotected object key;
         protected uint degree;
         protected ArrayList treeList=new ArrayList();
         //protected uint height=0;//暫時默認為0
         //create an empty tree whose attribute of degree is _degree
         public NaryTree(uint _degree)
         {
              //
              // TODO: 在此處添加構造函數邏輯
              //
              this.key=null;
              this.degree=_degree;
              this.treeList=null;
         }
         //構造一棵葉子結點的N叉樹
         public NaryTree(uint _degree,object _key)
         {
              this.key=_key;
              this.degree=_degree;
              this.treeList=new ArrayList();
              this.treeList.Capacity=(int)_degree;
              for(int i=0;i<this.treeList.Capacity;i++)
              {
                   this.treeList.Add( this.GetEmptyInstance(_degree) );
              }
         }
         //-----------------------------------------------------------------
         protected virtual object GetEmptyInstance(uint _degree)
         {    return new NaryTree(_degree); }
         //-------------------------------------------------------------------
         //judge whether the tree is an empty tree
         public override bool IsEmpty()
         {    return this.key==null; }
         //判定是否是葉子結點。如果即不是空樹且每一棵子樹均為空樹，則為葉子結點
         public override bool IsLeaf()
         {
              if(IsEmpty())
                   return false;
              for(uint i=0;i<this.degree;i++)
              {
                   if(  !(this[i].IsEmpty()) )
                       return false;
              }
              return true;
         }
         //-----------------------------------Inherited Attributes---------------------------------
         public override object Key
         {
              get
              {
                   return this.key;
              }
         }
         //索引器
         public override Tree this[uint _index]
         {
              get
              {
                   if( _index>=this.degree )
                       throw new Exception("My:out of index!");//如果出界，則拋出異常
                   if( this.IsEmpty() )
                       return null;//如果是空樹，則索引器返回一個 null
                   return (Tree)this.treeList[(int)_index];
              }
              set
              {
                   this.treeList[(int)_index]=value;
              }
         }